Workbench model :
TrimmedWindow (2) must use a TrimmedWindow
Part "mypartA"
PartSASHContainer
PartStack (3) must use a partstack
Part "mypartB" : this is the part with min/max buttons
Part
When i minimize "mypartB", the "minimized vertical toolbar" created take full size of TrimmedWindow and "mypartA" disappeared.